Definition: You are given a question on a random topic. You are also given 4 answer options (associated with "A", "B", "C", "D"), out of which only one is correct. You need to answer the question by selecting the correct option. You should only answer with the choice letter, not the whole answer.
Input: A clothes dryer that is set to run for 30 minutes is an example of which of the following control systems?
(A)Open loop (B)Closed loop (C)Negative feedback (D)Positive feedback

A